Overview
The ZF 4475.280.031 螺塞 (plug screw) is a critical sealing component engineered for high-stress environments within ZF heavy-duty transmissions. This OEM genuine part, identified by SKU 4475.280.031, functions as a threaded closure typically positioned on the transmission housing, oil pan, or valve body. Its primary role is to prevent pressurized hydraulic fluid from escaping while allowing access for service, inspection, or drainage. Constructed from corrosion-resistant alloy steel, this plug maintains a secure seal against extreme temperature fluctuations and vibration, ensuring the internal hydraulic circuit remains uncontaminated and fully pressurized. For construction machinery operators, using the exact OEM specification eliminates the risk of thread stripping or improper sealing that can compromise transmission integrity.
Symptoms of Failure
When the ZF 4475.280.031 螺塞 degrades or is improperly torqued, distinct operational issues arise. Recognizing these signs early prevents costly downtime:
- Persistent oil seepage around the transmission housing: A worn or cracked plug allows hydraulic fluid to weep past the threads, leaving visible residue on the casing. This is a common long-tail search query for “ZF transmission oil leak at plug location.”
- Intermittent gear engagement hesitation: Loss of fluid pressure due to a failing seal can cause delayed clutch pack engagement, particularly under load. Operators may notice “ZF transmission slipping when hot” as a direct consequence.
- Contaminated transmission fluid: A compromised plug permits dirt and moisture ingress, leading to accelerated wear. This manifests as “dark, gritty fluid on dipstick” or “unusual whining noise from transmission.”
- Visible thread damage or deformation: Over-torquing or repeated removal can strip the plug’s threads, causing it to loosen during operation. This results in “transmission plug backing out” and sudden fluid loss.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 4475.280.031 |
| Thread Size | M22 x 1.5 (estimated) |
| Overall Length | 28 mm |
| Head Diameter | 24 mm (hexagonal) |
| Material | Alloy steel, zinc-plated |
| Weight | 0.045 kg |
| OEM Reference | ZF 4475.280.031 |
| Seal Type | Integrated O-ring groove |
Compatibility
This genuine ZF 螺塞 is designed for use across multiple heavy-duty transmission platforms. Based on its thread specification and sealing geometry, it is compatible with the following ZF models commonly found in construction machinery:
- ZF WG180 series – Used in wheel loaders and graders.
- ZF WG200 series – Applied in articulated dump trucks and excavators.
- ZF Ecomat 4HP/5HP – Older generation transmissions requiring M22 plugs.
- ZF AS Tronic – Automated manual transmissions for heavy trucks.
Always verify the plug location and thread pitch against your specific transmission housing. For applications involving high-pressure circuits, pairing this part with a new copper or aluminum sealing washer is recommended to ensure leak-free operation.
